Luminescence Properties of Mesoporous Silica

Hindawi Publishing CorporationJournal of NanomaterialsVolume 2013 Article ID 918369 11 pageshttpdxdoiorg1011552013918369

Research ArticleLuminescence Properties of Mesoporous SilicaNanoparticles Encapsulating Different Europium ComplexesApplication for Biolabelling

S Lechevallier1 J Jorge2 R M Silveira2 N Ratel-Ramond1 D Neumeyer1

M J Menu3 M Gressier3 A L Marccedilal4 A L Rocha4 M A U Martines2

E Magdeleine5 J Dexpert-Ghys1 and M Verelst1

1 Centre drsquoElaboration de Materiaux et drsquoEtudes Structurales Universite de Toulouse 29 rue Jeanne Marvig BP 9434731055 Toulouse Cedex 4 France

2 CCET Universidade Federal de Mato Grosso do Sul Campo Grande MS Brazil3 Centre Interuniversitaire de Recherche et drsquoIngenierie des Materiaux UPS-CNRS 5085 Universite de Toulouse118 route de Narbonne 31062 Toulouse Cedex 9 France

4Universidade De Franca Franca SP Brazil5 ICELLTIS Prologue 1 815 La Pyreneenne 31670 Labege France

Correspondence should be addressed to S Lechevallier severinelechevalliercemesfr

Received 5 April 2013 Accepted 25 June 2013

Academic Editor John Zhanhu Guo

Copyright copy 2013 S Lechevallier et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

In this work we have synthesized and characterized new hybrid nanoplatforms for luminescent biolabeling based on the conceptof Eu3+ complexes encapsulation in mesoporous silica nanoparticles (asymp100 nm) Eu complexes have been selected on the basis oftheir capability to be excited at 365 nm which is a currently available wavelength on routine epifluorescence microscope For Eucomplexes encapsulation two different routes have been used the first route consists in grafting the transition metal complex intothe silica wall surface The second way deals with impregnation of the mesoporous silica NPs with the Eu complex Using thesecond route a silica shell coating is realized to prevent any dye release and the best result has been obtained using Eu-BHHCTcomplex However the best solution appears to be the grafting of Eu(TTA)

3-Phen-Si to mesoporous silica NPs For this hybrid

mSiO2-Eu(TTA)

3(Phen-Si) full characterization of the nanoplatforms is also presented

1 Introduction

Recent breakthroughs in the synthesis of mesoporous silicamaterials with the control of the particle size the morphol-ogy and the porosity along with their chemical stabilityhave made silica matrices highly attractive as the structuralbasis for a wide variety of nanotechnological applicationssuch as adsorption catalysis sensing and separation [1ndash7] In addition some authors have highlighted that surface-functionalized mesoporous silica nanoparticle (MSN) mate-rials can be readily internalized by animal and plant cellswithout posing any cytotoxicity issue in vitro [8 9] These

new developments offer the possibility of designing a newgeneration of druggene delivery systems and biosensors forintracellular controlled release applications

Another possible application consists in encapsulating aluminescent dye in plain or mesoporous silica nanoparticlesfor optical biolabeling [10ndash12] For this goal the dyemoleculemust be perfectly trapped inside the mesoporous matrix inorder to prevent the leaching and bleaching effects Manydye molecules can be encapsulated inside mesoporous NPshowever we think that lanthanide complexes as Eu3+ or Tb3+have the strong competitive advantage (versus commercial

2 Journal of Nanomaterials

organic probes) to allow the time delayed measurement forcomplete extinction of the biological self-fluorescence duringthe measurement [13] Moreover encapsulated lanthanidechelates are not or weakly subjected to photobleaching orphotobleaking they are chemically very stable and non-toxicAll these factors constitutemajor advances as it has been welldemonstrated by Dr Jin and his team [14]

However formost luminescent Eu3+ andTb3+ complexesone of the major drawbacks is that optical excitation windowis limited to the far-UV (lt330 nm) range Far-UV excitationis often problematic in biology because it causes damages tothe cellular matter Excitation below 330 nm involves poortransmission in most optics is bulky expensive and haslimited light sources Most of commercial flow cytometersand microscopes are not used at these wavelengths [14ndash16]

Several longer-wavelength-sensitized Eu3+ complexeshave been developed in recent years [17ndash22] and used asbiolabels for time-resolved luminescence bioimaging appli-cations Their properties have been illustrated for exampleby the highly specific and sensitive imaging of an envi-ronmental pathogen that is Giardia lamblia [23] and bythe use of bioconjugated silica nanoparticles embedding aneuropium complex to mark cancerous cells [24] Howeverfor our knowledge encapsulation of such complexes insidemesoporous nanoparticles has not been done systematicallyThemain advantage of mesoporous NPs is their high loadingcapability compare to plain SiO

2NPs which can potentially

lead to brighter probes Consequently the main goal of thiswork is to encapsulate these new long wavelength-sensitizedEu3+ complexes and to characterize the derived new nanohy-brids for cellular labeling using light excitation in the NUVrange (355ndash365 nm) given by laser (or Hg lamp) sourcesavailable on flow cytometer or fluorescent microscope Toreach this goal we have used two different approaches Thefirst route consists in grafting transition metal complexesinto the silica wall surface by using a bifunctional ligandwhich can chelate the metal on one side and react withthe silica wall on the other side (samples named as mSiO

2-

XXX in the following) The second way is easier and consistsin impregnating the mesoporous silica NPs with the Eu3+complex and then to elaborate a silica shell coating which willprevent any dye release (samples named as mSiO

2XXX in

the following)

2 Experimental Section

21 Reagents and Materials Most reagents were purchasedfromSigma-AldrichNN1015840-Dimethylformamide (DMF) hex-ane chloroform and ethanol were of analytical grade andusedwithout any further purification Eu(NO

3)3was aqueous

stock solution from Rhodia

22 Chemical Synthesis

221 Synthesis of Mesoporous Silica Nanoparticles (mSiO2)

Typically 02821 g of NaOH (PRS Panreac) and 1048 g ofcetyltrimethylammonium bromide (CTAB) were mixed with480mL of distilled water After this the mixture was kept

under constant stirring and the temperature was increasedup to 80∘C 5mL of tetraethyl orthosilicate (TEOS) wasadded as the silica precursor dropwise slowly (in 20minapproximately)Themixture was kept at 80∘Cunder vigorousstirring for 20 hThe obtained precipitate was centrifuged andwashedwithwaterThe sedimented productwas rapidly driedin an oven at 60∘C and then treated at 500∘C for 5 h (increase1∘Cmin) in order to decompose all the surfactantsThe finalweight of the obtained silica was approximately 10 g

222 Synthesis of Eu(TTA)3(Phen-Si) and Grafting in mSiO

2

Eu(TTA)3(Phen-Si) complex was prepared via a two-step

process as shown in Figure 1

(a) Synthesis of Ligand Phen-Si The ligand was preparedaccording to the procedures described by Li et al [25 26]Typically 5-amino-110-phenanthroline (41mmol 8004mg)was dissolved in CH

3Cl (75mL) and 3-(triethoxysilyl)propyl

isocyanate (45mmol 111mL) was added to the solutionThe mixture was then reduced to a volume of 5mL andrefluxed at 65∘C under Ar overnight Cold hexane was thenadded to precipitate the powderThis powderwas collected bycentrifugation washedwith hexane and dried under vacuumovernight

Elemental analysis for C22H30N4O4Si found

(calcd) C 528 (574) H 57 (622) N 121 (134) 1HNMR(30013MHz CDCl

3 120575H ppm) 063 (2H m CH

2 14-H) 110

(9H t 119869AB 7 CH3 16-H) 168 (2H m CH2 13-H) 334 (2H

m CH2 12-H) 375 (6H q 119869AB 7 CH

2 15-H) 634 (1H br

CH 7-H) 720 (1H dd CH 31015840-H) 757 (1H dd CH 3-H)815 (1H m CH 41015840-H) 818 (1H br NH 11-H) 837 (1H mCH 4-H) 838 (1H br NH 9-H) 886 (1H m CH 21015840-H)900 (1H m CH 2-H) 13C1H NMR (755MHz CDCl

3 120575c

ppm) 77 (s CH2 14) 183 (s CH

3 16) 237 (s CH

2 13) 428

(s CH2 12) 584 (s CH

2 15) 1181 (s CH 7) 1224 (s CH

31015840) 1235 (s CH 3) 1250 (s C 6) 1290 (s C 51015840) 1310 (sCH 41015840) 1328 (s C 5) 1359 (s CH 4) 1430 (s C 61015840) 1462(s C 8) 1490 (s CH 21015840) 1496 (s CH 2) 1568 (s C 10)

(b) Synthesis of Complex Eu(TTA)3(Phen-Si) The complex

was prepared according to the procedure described by Duanet al [28] 2-Thenoyltrifluoroacetone (TTA) (6mmol 1332 g)was dissolved in 20mL of absolute ethanol and triethylamine(6mmol 081mL) was added After 10min of stirring theligand (Phen-Si) (2mmol 0738 g) was added followed byEu(NO

3)3(2mmol 0517 g)The reactionmixture was heated

at 50ndash60∘C and stirred under Ar for an appropriate time(3ndash5 h) The reaction mixture was then cooled to roomtemperature and the solvent was removed at 40∘C underreduced pressure until obtaining a powder Then the powderwas washed with water and centrifuged The crude productwas then recrystallized by refluxing in ethanol to obtain thedesired product which was collected by filtration and driedunder vacuum at 40∘C

Elemental analysis for C46H39N4O10F9S3SiEu found

(calcd) C 414 (440) H 36 (31) N 82 (816) SM (mz)found 8399 Calc for (Eu(Phen-Si)(TTA)(NO

3))+ 837 IR

(KBr cmminus1) 2945 ]as (CH2 CH3) 2808 ]s (CH2 CH3) 1546

Journal of Nanomaterials 3

+

NH2

O O OO

OO

O

OC N

N N

N

NSi

SiCHCl365∘C

23

45

6 78

9

10

11

12

13

14

15

16

29984003998400

4998400

5998400

6998400

H H

(a)

3 CF3

O

O O

S+ Eu(NO3)3 +

N

N

N N SiOEt

OEtOEt

NEtEtOH50∘C3ndash5 h

CF3

O O

O

S

N N N

N

SiOEt

OEtEtO

Eu

3

(b)

Figure 1 Chemical structure of (a) the silylated phenanthroline ligand (Phen-Si) (and carbon atom numbering related to NMR data) and(b) the Eu(TTA)

3(Phen-Si) complex

1500 ] (C=O) 1440 1423 1385 ]as (CndashC=C) aromatic 737 668120574 (=CndashH) aromatic

(c) Grafting of Eu(TTA)3(Phen-Si) into mSiO

2Nanoparticles

The grafting was carried out according to amodified protocolfrom Rocha et al [27] mSiO

2NPs were suspended in

DMF 942 120583molg of Eu(TTA)3(Phen-Si) complex was also

suspended with DMFThen the two suspensions were mixedand the final concentration of mSiO

2was 1mgmLThe mix-

ture was refluxed for 24 h The powder was then centrifugedwashed three timeswith ethanol and dried at 80∘C in an ovenovernightThe europium content determined by TEM-EDXis 01 (mol)

223 Synthesis of Si-DBM-Eu(DBM)2Complex and

Grafting in mSiO2

(a) Preparation of Sodium 120573-Diketonate (Na-DBM) Theligand was prepared according to the procedure described byMachado et al [29] and De Oliveira et al [30] Na(s) (07 g300mmol) was dissolved in 30mL of anhydrous methanolunder an argon atmosphere to produce sodium methoxide67 g (300mmol) of dibenzoylmethane (DBM) was addedto the methoxide solvent to obtain a viscous suspensionSubsequently the powder was collected by filtration washed

with anhydrous methanol and dried under vacuum at 50∘Cproducing Na-DBM with a yield of 85

(b) Synthesis of Silylant Agent with 3-Chloropropyltrime-thoxysilane (TMOSCl) TMOSCl (113mL 60mmol) and1482 g (60mmol) of Na-DBM were added to 30mL ofanhydrous methanol The solution was stirred under argonatmosphere at 50∘C for 24 hThe silylating agent was denotedby Na(Si-DBM) Figure 2 shows the chemical structure thatrepresents this process

(c) Grafting of Na(Si-DBM) inside mSiO2Nanoparticles Com-

plexation with Eu3+ The grafting was carried out accordingto a modified protocol from Rocha et al [27] mSiO

2NPs

(50mg) were added to anhydrous ethanol (035mol) and 30NH4OH (10mmol) mixture Na(Si-DBM) solution (131mL)

was then added to the above mixture that was then stirredfor 1 h The powder was then centrifuged washed threetimes with ethanol and dried at 50∘C in an oven overnightFinally the powder was suspended in anhydrous ethanol(10mL) containing EuCl

3(235mL 010molsdotLminus1) producing

mSiO2-Eu(Si-DBM) To complete the coordination sphere

of Eu3+ 20mg of DBM-Na was added to produce the finalluminescent material SiDBM-Eu(DBM)

2[30] The powder

was again centrifuged washed three times with ethanol anddried at 50∘C in an oven overnight


H3C

H3C

CH3

O

O

O

SiH3C

H3C

CH3

O

O

O

O

O

O

O

Si

Cl

TMOSCl

+ +

Na-DBM

Na+

Na+ HCl

Na(Si-DBM)

Figure 2 Chemical structure of the silylated Na(Si-DBM) ligand [27]

5001000150020002500300035004000

Wavenumber (cmminus1)

40060080010001200140016001800Wavenumber (cmminus1)

T(

)T

()

Figure 3 FTIR spectrum of Si-DBM-Eu(DBM)2

FTIR spectrum of sample is presented Figure 3 Thetypical bands of bothDBMand silica structure such as a largeband centered on 3434 cmminus1 assigned to OH stretching ofsilanol groups of inorganic mesoporous structure of materialand also adsorbed andor bonded water can be seen Threepeaks at 2964 2923 and 2852 cmminus1 are related to CndashHstretching of CH

2and CH

3groups The mesoporous silica

structure can also be seen with the bands at 1065 805 and455 cmminus1 corresponding to the different SindashOndashSi vibrations(stretching bending and rocking resp) Signal related to thebeta-diketone can also be observed with the four bands at1597 1548 1458 and 1313 cmminus1 corresponding respectivelyto ]as (C=O) ] (C=C) ]s (C=O) and ]as (CndashC) of DBM [30]Europium content has been quantified by EDX-MET and hasbeen found to be 004 (mol)

224 Impregnation of mSiO2NPs with Eu(DBM)

3(Phen) and

Eu(BHHCT) Complexes

(a) Synthesis of Eu(DBM)3(Phen) and mSiO

2Impregnation

The complex was prepared according to Melby et al [31]with some modifications The ligand was first deprotonatedby addition of 1136 120583L of a solution of KOH in methanol

0990molsdotLminus1 to 750120583L of an ethanolic solution of diben-zoylmethane (DBM) 0150molsdotLminus1 followed by 375120583L of anethanolic solution of 110-phenantroline 01molsdotLminus1 Then375 120583L of an aqueous solution of Eu(NO

3)301molsdotLminus1 was

added dropwise under magnetic stirring to give the pre-cipitated complex [Eu(DBM)

3(Phen)] This suspension was

stirred for 24 h at room temperature and then centrifugedThe precipitate was carefully washed with ethanol recoveredby centrifugation and dried at 60∘C in air overnight Thecomplex was then dissolved in DMSO and stirred with30mg of mesoporous silica nanoparticles during 24 h atroom temperature in order to encapsulate it The amountof europium complex impregnated was calculated to be625 120583mol per 5mg of mesoporous silica Finally the samplewas coated with silica-amine shell as described in the nexttopics After analysis the Eu3+ content has found to be 042(mol)

(b) Synthesis of Eu(BHHCT) Complex and mSiO2Impreg-

nationThe ligand 440-bis(110158401015840110158401015840110158401015840210158401015840210158401015840310158401015840310158401015840-heptafluoro-410158401015840610158401015840-hexanedion-610158401015840-yl) chlorosulfo-o-terphenyl (BHHCT)was prepared as previously reported [32] In order to formthe complex Eu-BHHCT 5mg (625120583mol) of BHHCT ligandwas dissolved in 15mL of propanol 229mg (625 120583mol) ofEuCl3sdot6H2O was dissolved in 025mL of distilled water and

then added to the BHHCT solutionThe mixture was aged atroom temperature in darkness in order to form the complexThen 5mg of mesoporous silica nanoparticles was added tothe complex solution and the suspension was kept understirring for one night at room temperature in darkness Inorder to prevent any leak of the impregnated complex thesilica coating was elaborated without any purification How-ever after silica coating Eu3+ content has been determinedby MET-EDX and was found to be 1 (mol)

(c) Aminosilane Coating In order to avoid the leak of theimpregnated complexes the nanocapsules were closed bycoating them with a thin silica layer Typically 30mg ofimpregnated silica nanoparticles was dissolved in 80mL ofpropanol under ultrasound for 2 hThen 894mL of NH

4OH

(28) 75mL of distilled water and 25120583L of TEOS wereadded to the mixture and stirred at 40∘C for 2 h Then100 120583L of (3-aminopropyl)trimethoxysilane (APTMS) wasadded and the mixture stirred for 1 more hour The reaction


(a) (b)

Figure 4 SEM (a) and TEM (b) images of synthetized mesoporous silica nanoparticles (mSiO2)

2 40

2000

q (nmminus1)

Ilowast

q(n

mminus1)

Figure 5 SAXS diagram of synthetizedmesoporous silica nanopar-ticles (mSiO

2)

mixture is then centrifuged and washed with propanol andthe obtained precipitate is dried in oven overnight The finalweight of the material was approximately 45mg Note thatthe APTMS molecule does not play any role to prevent thedye release This molecule has been added at the end of thecoating protocol in order to introduce amine functions whichare very useful for further biofunctionalization

23 Physical and Chemical Characterizations 1H and13CNMR spectra were recorded on Bruker Advance300 with chemical shifts (in ppm) reported relative totetramethylsilane Mass spectra were recorded by FAB or IStechniques using a Normas R10-10 spectrometer Elementalanalyses were performed on elementary analyses (EA)which were performed using a Perkin Elmer 2400 series IIelemental analyser Chemical bonding was characterized byinfrared spectroscopy using a Perkin Elmer spectrometer100 series Samples were prepared by mixing the powders

with potassium bromide (1100 by weight) in a pelletNitrogen adsorption-desorption curves were measured witha Belsorp-mini (BEL Japan Inc) between 0 and 99 pp

0at

77 K Pretreatmentwas performed under vacuumduring 24 hat 80∘C Small angle X-ray scattering (SAXS) analyses wereperformed on an INEL XRG3D device Small angle X-rayscattering signal from mesoporous silica was obtained withX-rays produced by a Cu anode The X-ray beam was thenfiltered and focused onto the specimen using Kirkpatrick-Baez mirrors thus delimiting a small and nondivergentbeam Scattered intensity was recorded on an imaging platelocated 38 cm behind the specimen Particle shape size andcomposition were examinated by Transmission ElectronMicroscopy (TEM) using Philips CM20 FEG microscopeequipped with EDX detector This EDX detector was used toquantify Eu contents of samples Fluorescence spectra wererecorded with a Fluorolog FL3-22 Jobin Yvon spectrometerequipped with a R928 Hamamatsu photomultiplier and a450W excitation lamp For the analysis of emission decayversus time a pulsed Xe source was employed The emissiondecays have been recorded under excitation at 365 nmmonitoring the 5D

0rarr

7F2at its maximum (612 nm)

Experimental decays have been calculated according theformula 120591 = [intinfin

0119905 lowast 119868(119905)119889119905][int

infin

0119868(119905)] with an error range

estimated to be 15

24 Cell Culture Cytotoxicity Test and Fluorescence ImagingAn indirect cytotoxicity test was performed using an elutionmethod as described previously [33]The used cells areMDA-MB231 which are triple negative breast cancer cells [34]The cells are maintained in culture in RPMI 1640 mediumcomplemented with 10 fetal bovine serum 1 penicillin-streptomycin and incubated at 37∘Cwith 5CO

2 For in vitro

labeling as for cytotoxic tests cells were placed in 96-wellplate at 10000 cellswell The particles were added at differentconcentrations to the cell medium after sonicationTheMTT(methyl thiazoletetrazolium Sigma) test is used to evaluatethe viability of the MDA-MB231 in the presence of different


550 600 650 700

S1c

R1(C

PS120583

A)

Wavelength (nm)

mSiO2-Eu(Si-DBM)mSiO2-Eu(TTA)3(Phen-Si)

mSiO2Eu-BHHCTmSiO2Eu(DBM)3Phen

(a)

250 300 350 400 450 500Wavelength (nm)


S1R

1c (

CPS

120583A

)


(b)

Figure 6 (a) Emission spectra (120582ex = 365 nm) and (b) excitation spectra (120582em = 612 nm) of Eu(Si-DBM)3 Eu(DBM)

3-Phen Eu-BHHCT

and Eu(TTA)3(Phen-Si) complexes incorporated in mSiO

2 Particle concentration = 025mgsdotmLminus1 in water

5001000150020002500300035004000

Eu(TTA)3(Phen-Si)Wavenumber (cmminus1)

mSiO2

T(

)

mSiO2Eu(TTA)3(Phen-Si)

Figure 7 IR spectra of mSiO2 Eu(TTA)

3(Phen-Si) and mSiO

2-

Eu(TTA)3(Phen-Si)

concentrations of the NPs (mSiO2-Eu(TTA)

3(Phen-Si)) one

and three days after their addition to cell culture mediumMTT test is a colorimetric assay for measuring the activityof enzymes that reduce MTT to formazan dye giving apurple color DMSO (dimethylsulfoxide) solution is added todissolve the insoluble purple formazan product into a coloredsolution The absorbance of this colored solution can bequantified by measuring at 570 nm by a spectrophotometer

For in vitro labeling cells were incubated with NPs(01mgmL 24 h) Microscopic images were obtained usinga ldquohome-maderdquo Time Gated Luminescence Microscope(TGLM) kindly built for us by Dr Dayong Jin from Mac-quarie University of Sydney The main interest of a TGLM

is to be able to separate long-lasting fluorescence comingfrom lanthanides from self-fluorescence coming from thebiological media [23]

3 Results and Discussion

31 Synthesis of Mesoporous Silica Nanoparticles The synthe-sis procedure is based on the protocol proposed by [35] Aftera full optimization procedure with many varying parametersas reactant concentration (TEOS 093mmol to 47mmol andCTAB 077mmol to 71mmol) temperature (25 to 90∘C) andreaction time (2 to 20 h) we find that the best results (averagesize close to 100 nm spherical shape no agglomerationhigh surface area and a high porous volume) were obtainedwith the procedure reported in Section 2 Figure 4 showsSEM images (a) of particles Average particle size (feretdiameter counted on 242 particles) is 116 nm with a standarddeviation of 45 nm On the TEM image of Figure 4(b) onecan clearly see the well-ordered mesoporous structure ofparticles SAXS analysis presented in Figure 5 is characteristicof a hexagonal MCM 41 well-organized mesostructure [36]with three visible diffraction peaks d(100) = 337 A d(110)= 222 A and d(200) = 191 A The adsorptiondesorptionisotherm (BET) experiments done at 77K under nitrogengive a specific surface area equal to 1018m2 gminus1 The averagepore size is centered at 5476 nmwhereas total porous volumeis estimated at 1397 cm3 gminus1

32 Comparison of Luminescent Properties of Eu ComplexesIncorporated in mSiO

2 In order to verify that no release of

complexes occurs in aqueous solution we have checked thatnanoplatforms do not lose luminescence intensity (lt5) aftersevere water leaching (3times 1 h in water) Then to compareperformance of the different luminescent nanoplatforms


(a) (b)

(c) (d)

Figure 8 Electron microscope images and elemental cartography of mSiO2-Eu(TTA)

3(Phen-Si) (a) STEM image (b) Si cartography (c) N

cartography and (d) Eu cartography

we have recorded an emission spectrum after excitation at365 nm (laser diode or Hg lamp wave length usually foundonmany epifluorescencemicroscope) under exactly the samecondition (025mgsdotmLminus1 of NPs in water) Results presentedin Figure 6 show that all complexes have a maximumemission band centred around 613 nm However emissionintensities recorded under the same conditions are differentThe sample presenting the most intense luminescence isthe one with Eu(TTA)

3(Phen-Si) complex grafted inside

the mesopores of the mSiO2NPs As this sample presents

the highest luminescent intensity it has been selected forfurther characterization

33 Characterization of the Eu(TTA)3(Phen-Si) Complex

Grafted in mSiO2 Eu(TTA)

3(Phen-Si) complex was suc-

cessfully prepared via a two steps process as shown inFigure 1 Ligand (Phen-Si) was first obtained by reacting 5-amino-110-phenanthroline and 3-(triethoxysilyl)propyl iso-cyanate (Figure 1(a)) Europium complex was then pre-pared from Eu(NO

3)3 2-thenoyltrifluoroacetone (TTA) and

phenantroline ligand (Phen-Si) in the presence of triethy-lamine in ethanol at 50ndash60∘C (Figure 1(b)) Figure 7 showsinfrared spectra of Eu(TTA)

3(Phen-Si) complex mSiO

2 and

the sample of mSiO2incorporating the complex (mSiO

2-

Eu(TTA)3(Phen-Si)) The spectrum of the complex presents

the characteristic bands of phenanthroline as well as thoseof TTA indicating that the complex has been obtained Onthe mSiO

2spectrum the well-known bands of SiO

2are

observed The mSiO2-Eu(TTA)

3(Phen-Si) spectrum exhibits

both bands of the complex and mSiO2 especially in the

region of 1700ndash600 cmminus1The sample mSiO

2-Eu(TTA)

3(Phen-Si) has also been

investigated by BET analysis After loading the porousvolume decreases down to 09570m3sdotgminus1 (instead of1397m3sdotgminus1) as well as the specific area to 684m2sdotgminus1(instead of 1018m2sdotgminus1) This loss of porous volume andspecific area confirms that the complex Eu(TTA)

3(Phen-Si)

is well grafted into the mesopores of the NPsFigure 8 presents the elemental cartography obtained by

EDX spectroscopy on STEM microscopy It can be seen thatafter incorporation mSiO

2keeps its spherical shape without

any aggregation EDX spectroscopy results show that siliconatoms are homogenously dispersed to form the mesoporoussilica matrix (Figure 8(b)) Nitrogen and europium atomsare also detected corresponding to the grafted complex(Figures 8(c) and 8(d)) Images reveal that these elements arehomogenously well dispersed all inside the NPs confirmingthe good repartition of the complex all around the walls ofthe mesoporous silica

In Figure 9(a) emission spectra of the grafted complexrecorded in ethanol after excitation at 365 nm are gatheredFor the free complex the concentration was 025mgsdotmLminus1corresponding to 2sdot10minus4molsdotLminus1 in Eu3+ and for the graftedcomplex the concentration was 1mgsdotmLminus1 correspondingto 2sdot10minus5molL in Eu3+ (considering a grafting rate of01 (mol)) The characteristic emission lines of transitions5D0rarr

7F119869of Eu3+ are observed for both samples Some

differences may be noticed for instance the shape of the


500 550 600 650 700 750120582 (nm)

mSiO2

mSiO2-Eu(TTA)3(Phen-Si)Eu(TTA)3(Phen-Si)

5D0rarr7F0

5D0rarr7F1

5D0rarr7F2

5D0rarr7F3

5D0rarr7F4

I(a

u)

(a)

mSiO2


250 300 350 400 450120582 (nm)

I(a

u)

(b)

0 05 1 15 2 25 3 35 40

1 times 107

2 times 107

3 times 107

4 times 107

5 times 107

6 times 107

Time (ms)

Eu(TTA)3(Phen-Si)mSiO2-Eu(TTA)3(Phen-Si)

I(a

u)

(c)

Figure 9 (a) Emission spectra recorded after excitation at 365 nm (b) excitation spectra recorded at 612 nm and (c) emission decay curvesrecorded at 612 nm under excitation at 365 nm for pure Eu(TTA)

3(Phen-Si) complex and mSiO

2-Eu(TTA)

3(Phen-Si)

0

005

01

015

02

0 01 05 1 2

DO

NPs concentration (mgmL)

Figure 10 Cytotoxicity test of mSiO2-Eu(TTA)

3(Phen-Si) The

higher is the DO the higher is the living cells number

5D0rarr

7F1transition and relative intensities of 5D

0rarr

7F45D0rarr

7F2 Figure 9(b) presents excitation spectra for

these samples observed at 612 nm For the free complex onebroad band centred on 360 nm can be seen After incorpo-ration into mSiO

2this broad band remains but seems to

be shifted to higher energy around 330 nm This is probablydue to the covalent grafting of the complex into mSiO

2

which modifies energy transfers from the antenna to Eu3+ions The 5D

0luminescence decays for the free complex and

the complex grafted intomSiO2are shown in Figure 9(c)The

free complex exhibits monoexponential decay 119868 = 1198680sdot 119890(minus119905120591)

with lifetime 120591 = 06plusmn006ms For grafted complex the decayis clearly biexponential the faster component is the sameas for pure complex but a slower component with lifetime


(a) (b)

Figure 11 Internalization of mSiO2-Eu(TTA)

3(Phen-Si) in MDA-MB231 cancer cells after exposure to NPs (overnight 01mgsdotmLminus1) (a)

Representative bright field images + UV excitation (120582ex 365 nm the blue color comes from the nucleus colored with DAPE used to help cellsdetection) (b) UV excitation (120582ex 365 nm) and time gated detection of Eu(TTA)

3(Phen-Si)

estimated to about 1ms is also observed The average decayestimated with the formula 120591 = [intinfin

0119905 lowast 119868(119905)119889119905][int

infin

0119868(119905)]

is 120591 = 080 plusmn 008ms From the comparison of emissionspectra and of emission decays at least two populationsof Eu3+ are then observed after grafting into mSiO

2 A

detailed investigation of luminescence data necessary todiscuss the possible structures of these populations is beyondthe scope of this paper It is important to notice here twoessential features for the potential applicationsThe first pointis the red emission observed for the dispersed NPs andthe pure complex in solution both excited at 365 nm thatis in the organic antenna and recorded under the sameexperimental conditions and have the same intensities Theother point of interest is that the emission lifetime of thegrafted NPs is suitable for microsecond time gated detectionof luminescence

34 Cytotoxicity Tests on Nanoparticles The optical density(OD) is directly proportional to the living cells numberThe comparison of the proliferation of MDA-MB231 cancercells in contact (during 3 days) with growing concentrationsof NPs 01 05 1 and 2mgmL emphasizes a significantdecrease of cell viability and an inhibition of cell growth fordoses of NPs higher than 01mgsdotmLminus1 (Figure 10) Neverthe-less for particles of concentration around 100 120583gsdotmLminus1 weconsider that the cytotoxicity of NPs is negligible

35 Observation of Particles Fluorescence in Living Cells Thespherical mSiO

2-Eu(TTA)

3(Phen-Si) NPs have been allowed

to react with MDA-MB231 cancer cells under conditionswhere NPs are shown to be noncytotoxic (01mgsdotmLminus1)overnight Images in Figure 11 show that NPs have beeninternalized by the cells Indeed a strong red fluorescenceis observed in their cytoplasm with a higher intensity in the

perinuclear area The nucleus stained in blue with DAPEappears to be totally free of NPs as shown by time gateddetection Time gated detection collects the emission lightonly 100 120583s after the excitation keeping only the long-lastingluminescence of Eu3+ and removing all the backgroundcoming from the DAPE dye and self-fluorescence of thebiological media [14]

4 Conclusion

We have synthesized new hybrid nanoplatforms for lumi-nescent biolabeling based on the concept of Eu3+ com-plexes encapsulation inside mesoporous silica nanoparticlesEuropium complexes have been selected on the basis oftheir capability to be exited at 365 nm which is a wavelengthcurrently available on routine epifluorescence microscopeFor Eu3+ complexes encapsulation two different routes havebeen used the first route consists in grafting the transitionmetal complexes into the silica wall surface The second waydeals with physicochemical impregnation of the mesoporoussilica NPs with the Eu complexThen a silica shell coating willprevent any dye release For this last protocol the best resulthas been obtained using Eu-BHHCCT complex Howeverthe best solution appears to be Eu(TTA)

3(Phen-Si) complex

covalently grafted inside the mesoporous silica NPs

References

[1] B I Slowing B G Trewyn S Giri and V S-Y Lin ldquoMeso-porous silica nanoparticles for drug delivery and biosensingapplicationsrdquo Advanced Functional Materials vol 17 no 8 pp1225ndash1236 2007

[2] S Huh J W Wiench J-C Yoo M Pruski and V S-YLin ldquoOrganic functionalization and morphology control of


mesoporous silicas via a co-condensation synthesis methodrdquoChemistry of Materials vol 15 no 22 pp 4247ndash4256 2003

[3] B G Trewyn CMWhitman and V S-Y Lin ldquoMorphologicalcontrol of room-temperature ionic liquid templated meso-porous silica nanoparticles for controlled release of antibacterialagentsrdquo Nano Letters vol 4 no 11 pp 2139ndash2143 2004

[4] K Suzuki K Ikari and H Imai ldquoSynthesis of silica nanopar-ticles having a well-ordered mesostructure using a doublesurfactant systemrdquo Journal of the American Chemical Societyvol 126 no 2 pp 462ndash463 2004

[5] J Y Ying ldquoDesign and synthesis of nanostructured catalystsrdquoChemical Engineering Science vol 61 no 5 pp 1540ndash1548 2006

[6] J Y Ying C P Mehnert andM SWong ldquoA new type of metal-organic large-pore zeotyperdquo Angewandte Chemie vol 38 no 1-2 pp 153ndash156 1999

[7] C T Kresge M E Leonowicz W J Roth J C Vartuli and J SBeck ldquoOrdered mesoporous molecular sieves synthesized by aliquid-crystal template mechanismrdquo Nature vol 359 no 6397pp 710ndash712 1992

[8] D R Radu C-Y Lai K Jeftinija E W Rowe S Jeftinija and VS-Y Lin ldquoA polyamidoamine dendrimer-capped mesoporoussilica nanosphere-based gene transfection reagentrdquo Journal ofthe American Chemical Society vol 126 no 41 pp 13216ndash132172004

[9] I Slowing B G Trewyn and V S Y Lin ldquoEffect of surfacefunctionalization of MCM-41-type mesoporous silica nanopar-ticles on the endocytosis by human cancer cellsrdquo Journal of theAmerican Chemical Society vol 128 no 46 pp 14792ndash147932006

[10] X Zhao R A P Bagwe andW Tan ldquoDevelopment of organic-dye-doped silica nanoparticles in a reverse microemulsionrdquoAdvanced Materials vol 16 no 2 pp 173ndash176 2004

[11] L M Rossi L Shi F H Quina and Z Rosenzweig ldquoStobersynthesis ofmonodispersed luminescent silica nanoparticles forbioanalytical assaysrdquo Langmuir vol 21 no 10 pp 4277ndash42802005

[12] S Cousinie L Mauline M Gressier et al ldquoBulk or surfacegrafted silylated Ru(II) complexes on silica as luminescentnanomaterialsrdquo New Journal of Chemistry vol 36 no 6 pp1355ndash1367 2012

[13] H L Handl and R J Gillies ldquoLanthanide-based luminescentassays for ligand-receptor interactionsrdquo Life Sciences vol 77 no4 pp 361ndash371 2005

[14] D Jin and J A Piper ldquoTime-gated luminescence microscopyallowing direct visual inspection of lanthanide-stained micro-organisms in background-free conditionrdquoAnalytical Chemistryvol 83 no 6 pp 2294ndash2300 2011

[15] L Jiang J WuW Guilan et al ldquoDevelopment of a visible-light-sensitized europium complex for time-resolved fluorometricapplicationrdquoAnalytical Chemistry vol 82 no 6 pp 2529ndash25352010

[16] R Connally D Jin and J Piper ldquoHigh intensity solid-state UVsource for time-gated luminescence microscopyrdquo CytometryPart A vol 69 no 9 pp 1020ndash1027 2006

[17] Y BretonniereM J CannD Parker andR Slater ldquoRatiometricprobes for hydrogencarbonate analysis in intracellular or extra-cellular environments using europium luminescencerdquoChemicalCommunications no 17 pp 1930ndash1931 2002

[18] J Yu D Parker R Pal R A Poole andM J Cann ldquoA europiumcomplex that selectively stains nucleoli of cellsrdquo Journal of theAmerican Chemical Society vol 128 no 7 pp 2294ndash2299 2006

[19] R Pal and D Parker ldquoA single component ratiometric pHprobe with long wavelength excitation of europium emissionrdquoChemical Communications no 5 pp 474ndash476 2007

[20] MHVWertsMADuin JWHofstraat and JWVerhoevenldquoBathochromicity of Michlerrsquos ketone upon coordination withlanthanide(III) 120573-diketonates enables efficient sensitisation ofEu3+ for luminescence under visible light excitationrdquo ChemicalCommunications no 9 pp 799ndash800 1999

[21] C Yang L M Fu Y Wang et al ldquoa highly luminescenteuropium complex showing visible-light-sensitized red emis-sion direct observation of the singlet pathwayrdquo AngewandteChemie vol 43 no 38 pp 5010ndash5013 2004

[22] S M Borisov and O S Wolfbeis ldquoTemperature-sensitiveeuropium(III) probes and their use for simultaneous lumines-cent sensing of temperature and oxygenrdquo Analytical Chemistryvol 78 no 14 pp 5094ndash5101 2006

[23] J Wu Z Ye G Wang et al ldquoVisible-light-sensitized highlyluminescent europium nanoparticles preparation and appli-cation for time-gated luminescence bioimagingrdquo Journal ofMaterials Chemistry vol 19 no 9 pp 1258ndash1264 2009

[24] S V Eliseeva B Song C D B Vandevyver A-S Chauvin JB Wacker and J-C G Bunzli ldquoIncreasing the efficiency of lan-thanide luminescent bioprobes bioconjugated silica nanoparti-cles as markers for cancerous cellsrdquo New Journal of Chemistryvol 34 no 12 pp 2915ndash2921 2010

[25] M J Li Z Chen V W W Yam and Y Zu ldquoMultifunctionalruthenium(II) polypyridine complex-based core-shell mag-netic silica nanocomposites magnetism luminescence andelectrochemiluminescencerdquo ACS Nano vol 2 no 5 pp 905ndash912 2008

[26] H R Li J Lin H J Zhang L S Fu Q GMeng and S BWangldquoPreparation and luminescence properties of hybrid materialscontaining europium(III) complexes covalently bonded to asilica matrixrdquo Chemistry of Materials vol 14 no 9 pp 3651ndash3655 2002

[27] L A Rocha J M A Caiut Y Messaddeq et al ldquoNon-leachablehighly luminescent ordered mesoporous SiO

2spherical parti-

clesrdquo Nanotechnology vol 21 no 15 Article ID 155603 2010[28] J P Duan P P Dun and C H Cheng ldquoEuropium complexes

having an aminophenanthroline ligand as red dopants inelectroluminescent devicesrdquo AZojomo vol 1 2005

[29] J K F B Machado A L Marcal O J Lima K J CiuffiE J Nassar and P S Caleffi ldquoMateriais hıbridos organico-inorganicos (ormosil) obtidos por sol-gel com potencial usocomo filtro solarrdquo Quımica Nova vol 34 no 6 pp 945ndash9492011

[30] E De Oliveira C R Neri O A Serra and A G S PadroldquoAntenna effect in highly luminescent Eu

3+anchored in hexag-

onal mesoporous silicardquo Chemistry of Materials vol 19 no 22pp 5437ndash5442 2007

[31] L R Melby N J Rose E Abramson and J C Caris ldquoSynthesisand fluorescence of some trivalent lanthanide complexesrdquoJournal of the American Chemical Society vol 86 no 23 pp5117ndash5125 1964

[32] J L Yuan and K Matsumoto ldquoA new tetradentate 120573-diketonateminuseuropium chelate that can be covalently boundto proteins for time-resolved fluoroimmunoassayrdquo AnalyticalChemistry vol 70 no 3 pp 596ndash601 1998

[33] T Mosmann ldquoRapid colorimetric assay for cellular growth andsurvival application to proliferation and cytotoxicity assaysrdquoJournal of Immunological Methods vol 65 no 1-2 pp 55ndash631983


[34] B R Brinkley P T Beall and L J Wible ldquoVariations in cellformand cytoskeleton in humanbreast carcinoma cells in vitrordquoCancer Research vol 40 no 9 pp 3118ndash3129 1980

[35] Q He J Zhang J Shi et al ldquoThe effect of PEGylation ofmesoporous silica nanoparticles on nonspecific binding ofserum proteins and cellular responsesrdquo Biomaterials vol 31 no6 pp 1085ndash1092 2010

[36] D A Sheppard C F Maitland and C E Buckley ldquoPreliminaryresults of hydrogen adsorption and SAXS modelling of meso-porous silica MCM-41rdquo Journal of Alloys and Compounds vol404ndash406 pp 405ndash408 2005

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2013

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013


Polymer ScienceInternational Journal of

ISRN Corrosion



CompositesJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2013

International Journal of

BiomaterialsHindawi Publishing Corporationhttpwwwhindawicom Volume 2013

ISRN Ceramics


Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2013

MaterialsJournal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2013

Journal of

ISRN Materials Science


Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal

ISRN Nanotechnology


NanoparticlesJournal of


Smart Materials Research



MetallurgyJournal of

BioMed Research International


ISRN Polymer Science


Na

nom

ate

ria

ls


Journal ofNanomaterials


organic probes) to allow the time delayed measurement forcomplete extinction of the biological self-fluorescence duringthe measurement [13] Moreover encapsulated lanthanidechelates are not or weakly subjected to photobleaching orphotobleaking they are chemically very stable and non-toxicAll these factors constitutemajor advances as it has been welldemonstrated by Dr Jin and his team [14]

However formost luminescent Eu3+ andTb3+ complexesone of the major drawbacks is that optical excitation windowis limited to the far-UV (lt330 nm) range Far-UV excitationis often problematic in biology because it causes damages tothe cellular matter Excitation below 330 nm involves poortransmission in most optics is bulky expensive and haslimited light sources Most of commercial flow cytometersand microscopes are not used at these wavelengths [14ndash16]

Several longer-wavelength-sensitized Eu3+ complexeshave been developed in recent years [17ndash22] and used asbiolabels for time-resolved luminescence bioimaging appli-cations Their properties have been illustrated for exampleby the highly specific and sensitive imaging of an envi-ronmental pathogen that is Giardia lamblia [23] and bythe use of bioconjugated silica nanoparticles embedding aneuropium complex to mark cancerous cells [24] Howeverfor our knowledge encapsulation of such complexes insidemesoporous nanoparticles has not been done systematicallyThemain advantage of mesoporous NPs is their high loadingcapability compare to plain SiO

2NPs which can potentially

lead to brighter probes Consequently the main goal of thiswork is to encapsulate these new long wavelength-sensitizedEu3+ complexes and to characterize the derived new nanohy-brids for cellular labeling using light excitation in the NUVrange (355ndash365 nm) given by laser (or Hg lamp) sourcesavailable on flow cytometer or fluorescent microscope Toreach this goal we have used two different approaches Thefirst route consists in grafting transition metal complexesinto the silica wall surface by using a bifunctional ligandwhich can chelate the metal on one side and react withthe silica wall on the other side (samples named as mSiO

2-

XXX in the following) The second way is easier and consistsin impregnating the mesoporous silica NPs with the Eu3+complex and then to elaborate a silica shell coating which willprevent any dye release (samples named as mSiO

2XXX in

the following)

2 Experimental Section

21 Reagents and Materials Most reagents were purchasedfromSigma-AldrichNN1015840-Dimethylformamide (DMF) hex-ane chloroform and ethanol were of analytical grade andusedwithout any further purification Eu(NO

3)3was aqueous

stock solution from Rhodia

22 Chemical Synthesis

221 Synthesis of Mesoporous Silica Nanoparticles (mSiO2)

Typically 02821 g of NaOH (PRS Panreac) and 1048 g ofcetyltrimethylammonium bromide (CTAB) were mixed with480mL of distilled water After this the mixture was kept

under constant stirring and the temperature was increasedup to 80∘C 5mL of tetraethyl orthosilicate (TEOS) wasadded as the silica precursor dropwise slowly (in 20minapproximately)Themixture was kept at 80∘Cunder vigorousstirring for 20 hThe obtained precipitate was centrifuged andwashedwithwaterThe sedimented productwas rapidly driedin an oven at 60∘C and then treated at 500∘C for 5 h (increase1∘Cmin) in order to decompose all the surfactantsThe finalweight of the obtained silica was approximately 10 g

222 Synthesis of Eu(TTA)3(Phen-Si) and Grafting in mSiO

2

Eu(TTA)3(Phen-Si) complex was prepared via a two-step

process as shown in Figure 1

(a) Synthesis of Ligand Phen-Si The ligand was preparedaccording to the procedures described by Li et al [25 26]Typically 5-amino-110-phenanthroline (41mmol 8004mg)was dissolved in CH

3Cl (75mL) and 3-(triethoxysilyl)propyl

isocyanate (45mmol 111mL) was added to the solutionThe mixture was then reduced to a volume of 5mL andrefluxed at 65∘C under Ar overnight Cold hexane was thenadded to precipitate the powderThis powderwas collected bycentrifugation washedwith hexane and dried under vacuumovernight

Elemental analysis for C22H30N4O4Si found

(calcd) C 528 (574) H 57 (622) N 121 (134) 1HNMR(30013MHz CDCl

3 120575H ppm) 063 (2H m CH

2 14-H) 110

(9H t 119869AB 7 CH3 16-H) 168 (2H m CH2 13-H) 334 (2H

m CH2 12-H) 375 (6H q 119869AB 7 CH

2 15-H) 634 (1H br

CH 7-H) 720 (1H dd CH 31015840-H) 757 (1H dd CH 3-H)815 (1H m CH 41015840-H) 818 (1H br NH 11-H) 837 (1H mCH 4-H) 838 (1H br NH 9-H) 886 (1H m CH 21015840-H)900 (1H m CH 2-H) 13C1H NMR (755MHz CDCl

3 120575c

ppm) 77 (s CH2 14) 183 (s CH

3 16) 237 (s CH

2 13) 428

(s CH2 12) 584 (s CH

2 15) 1181 (s CH 7) 1224 (s CH

31015840) 1235 (s CH 3) 1250 (s C 6) 1290 (s C 51015840) 1310 (sCH 41015840) 1328 (s C 5) 1359 (s CH 4) 1430 (s C 61015840) 1462(s C 8) 1490 (s CH 21015840) 1496 (s CH 2) 1568 (s C 10)

(b) Synthesis of Complex Eu(TTA)3(Phen-Si) The complex

was prepared according to the procedure described by Duanet al [28] 2-Thenoyltrifluoroacetone (TTA) (6mmol 1332 g)was dissolved in 20mL of absolute ethanol and triethylamine(6mmol 081mL) was added After 10min of stirring theligand (Phen-Si) (2mmol 0738 g) was added followed byEu(NO

3)3(2mmol 0517 g)The reactionmixture was heated

at 50ndash60∘C and stirred under Ar for an appropriate time(3ndash5 h) The reaction mixture was then cooled to roomtemperature and the solvent was removed at 40∘C underreduced pressure until obtaining a powder Then the powderwas washed with water and centrifuged The crude productwas then recrystallized by refluxing in ethanol to obtain thedesired product which was collected by filtration and driedunder vacuum at 40∘C

Elemental analysis for C46H39N4O10F9S3SiEu found

(calcd) C 414 (440) H 36 (31) N 82 (816) SM (mz)found 8399 Calc for (Eu(Phen-Si)(TTA)(NO

3))+ 837 IR

(KBr cmminus1) 2945 ]as (CH2 CH3) 2808 ]s (CH2 CH3) 1546


+

NH2

O O OO

OO

O

OC N

N N

N

NSi

SiCHCl365∘C

23

45

6 78

9

10

11

12

13

14

15

16

29984003998400

4998400

5998400

6998400

H H

(a)

3 CF3

O

O O

S+ Eu(NO3)3 +

N

N

N N SiOEt

OEtOEt


CF3

O O

O

S

N N N

N

SiOEt

OEtEtO

Eu

3

(b)


3(Phen-Si) complex



2Nanoparticles





2was 1mgmLThe mix-



Grafting in mSiO2






2NPs






2[30] The powder



H3C

H3C

CH3

O

O

O

SiH3C

H3C

CH3

O

O

O

O

O

O

O

Si

Cl

TMOSCl

+ +

Na-DBM

Na+

Na+ HCl

Na(Si-DBM)


5001000150020002500300035004000



T(

)T

()



2and CH




3(Phen) and

Eu(BHHCT) Complexes


2Impregnation











4OH



(a) (b)


2 40

2000

q (nmminus1)

Ilowast

q(n

mminus1)


2)




0at


0rarr



0119905 lowast 119868(119905)119889119905][int

infin


estimated to be 15


2 For in vitro



550 600 650 700

S1c

R1(C

PS120583

A)

Wavelength (nm)



(a)

250 300 350 400 450 500Wavelength (nm)


S1R

1c (

CPS

120583A

)


(b)


3-Phen Eu-BHHCT



5001000150020002500300035004000


mSiO2

T(

)



3(Phen-Si) and mSiO

2-

Eu(TTA)3(Phen-Si)


3(Phen-Si)) one










(a) (b)

(c) (d)















2 and


2-




2are





2-Eu(TTA)



3(Phen-Si)









500 550 600 650 700 750120582 (nm)

mSiO2


5D0rarr7F0

5D0rarr7F1

5D0rarr7F2

5D0rarr7F3

5D0rarr7F4

I(a

u)

(a)

mSiO2


250 300 350 400 450120582 (nm)

I(a

u)

(b)

0 05 1 15 2 25 3 35 40

1 times 107

2 times 107

3 times 107

4 times 107

5 times 107

6 times 107

Time (ms)


I(a

u)

(c)



2-Eu(TTA)

3(Phen-Si)

0

005

01

015

02

0 01 05 1 2

DO



3(Phen-Si) The


5D0rarr


0rarr

7F45D0rarr





2







(a) (b)




3(Phen-Si)


0119905 lowast 119868(119905)119889119905][int

infin

0119868(119905)]


2 A




2-Eu(TTA)




4 Conclusion


3(Phen-Si) complex


References






























2spherical parti-




















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




+

NH2

O O OO

OO

O

OC N

N N

N

NSi

SiCHCl365∘C

23

45

6 78

9

10

11

12

13

14

15

16

29984003998400

4998400

5998400

6998400

H H

(a)

3 CF3

O

O O

S+ Eu(NO3)3 +

N

N

N N SiOEt

OEtOEt


CF3

O O

O

S

N N N

N

SiOEt

OEtEtO

Eu

3

(b)


3(Phen-Si) complex



2Nanoparticles





2was 1mgmLThe mix-



Grafting in mSiO2






2NPs






2[30] The powder



H3C

H3C

CH3

O

O

O

SiH3C

H3C

CH3

O

O

O

O

O

O

O

Si

Cl

TMOSCl

+ +

Na-DBM

Na+

Na+ HCl

Na(Si-DBM)


5001000150020002500300035004000



T(

)T

()



2and CH




3(Phen) and

Eu(BHHCT) Complexes


2Impregnation











4OH



(a) (b)


2 40

2000

q (nmminus1)

Ilowast

q(n

mminus1)


2)




0at


0rarr



0119905 lowast 119868(119905)119889119905][int

infin


estimated to be 15


2 For in vitro



550 600 650 700

S1c

R1(C

PS120583

A)

Wavelength (nm)



(a)

250 300 350 400 450 500Wavelength (nm)


S1R

1c (

CPS

120583A

)


(b)


3-Phen Eu-BHHCT



5001000150020002500300035004000


mSiO2

T(

)



3(Phen-Si) and mSiO

2-

Eu(TTA)3(Phen-Si)


3(Phen-Si)) one










(a) (b)

(c) (d)















2 and


2-




2are





2-Eu(TTA)



3(Phen-Si)









500 550 600 650 700 750120582 (nm)

mSiO2


5D0rarr7F0

5D0rarr7F1

5D0rarr7F2

5D0rarr7F3

5D0rarr7F4

I(a

u)

(a)

mSiO2


250 300 350 400 450120582 (nm)

I(a

u)

(b)

0 05 1 15 2 25 3 35 40

1 times 107

2 times 107

3 times 107

4 times 107

5 times 107

6 times 107

Time (ms)


I(a

u)

(c)



2-Eu(TTA)

3(Phen-Si)

0

005

01

015

02

0 01 05 1 2

DO



3(Phen-Si) The


5D0rarr


0rarr

7F45D0rarr





2







(a) (b)




3(Phen-Si)


0119905 lowast 119868(119905)119889119905][int

infin

0119868(119905)]


2 A




2-Eu(TTA)




4 Conclusion


3(Phen-Si) complex


References






























2spherical parti-




















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




H3C

H3C

CH3

O

O

O

SiH3C

H3C

CH3

O

O

O

O

O

O

O

Si

Cl

TMOSCl

+ +

Na-DBM

Na+

Na+ HCl

Na(Si-DBM)


5001000150020002500300035004000



T(

)T

()



2and CH




3(Phen) and

Eu(BHHCT) Complexes


2Impregnation











4OH



(a) (b)


2 40

2000

q (nmminus1)

Ilowast

q(n

mminus1)


2)




0at


0rarr



0119905 lowast 119868(119905)119889119905][int

infin


estimated to be 15


2 For in vitro



550 600 650 700

S1c

R1(C

PS120583

A)

Wavelength (nm)



(a)

250 300 350 400 450 500Wavelength (nm)


S1R

1c (

CPS

120583A

)


(b)


3-Phen Eu-BHHCT



5001000150020002500300035004000


mSiO2

T(

)



3(Phen-Si) and mSiO

2-

Eu(TTA)3(Phen-Si)


3(Phen-Si)) one










(a) (b)

(c) (d)















2 and


2-




2are





2-Eu(TTA)



3(Phen-Si)









500 550 600 650 700 750120582 (nm)

mSiO2


5D0rarr7F0

5D0rarr7F1

5D0rarr7F2

5D0rarr7F3

5D0rarr7F4

I(a

u)

(a)

mSiO2


250 300 350 400 450120582 (nm)

I(a

u)

(b)

0 05 1 15 2 25 3 35 40

1 times 107

2 times 107

3 times 107

4 times 107

5 times 107

6 times 107

Time (ms)


I(a

u)

(c)



2-Eu(TTA)

3(Phen-Si)

0

005

01

015

02

0 01 05 1 2

DO



3(Phen-Si) The


5D0rarr


0rarr

7F45D0rarr





2







(a) (b)




3(Phen-Si)


0119905 lowast 119868(119905)119889119905][int

infin

0119868(119905)]


2 A




2-Eu(TTA)




4 Conclusion


3(Phen-Si) complex


References






























2spherical parti-




















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




(a) (b)


2 40

2000

q (nmminus1)

Ilowast

q(n

mminus1)


2)




0at


0rarr



0119905 lowast 119868(119905)119889119905][int

infin


estimated to be 15


2 For in vitro



550 600 650 700

S1c

R1(C

PS120583

A)

Wavelength (nm)



(a)

250 300 350 400 450 500Wavelength (nm)


S1R

1c (

CPS

120583A

)


(b)


3-Phen Eu-BHHCT



5001000150020002500300035004000


mSiO2

T(

)



3(Phen-Si) and mSiO

2-

Eu(TTA)3(Phen-Si)


3(Phen-Si)) one










(a) (b)

(c) (d)















2 and


2-




2are





2-Eu(TTA)



3(Phen-Si)









500 550 600 650 700 750120582 (nm)

mSiO2


5D0rarr7F0

5D0rarr7F1

5D0rarr7F2

5D0rarr7F3

5D0rarr7F4

I(a

u)

(a)

mSiO2


250 300 350 400 450120582 (nm)

I(a

u)

(b)

0 05 1 15 2 25 3 35 40

1 times 107

2 times 107

3 times 107

4 times 107

5 times 107

6 times 107

Time (ms)


I(a

u)

(c)



2-Eu(TTA)

3(Phen-Si)

0

005

01

015

02

0 01 05 1 2

DO



3(Phen-Si) The


5D0rarr


0rarr

7F45D0rarr





2







(a) (b)




3(Phen-Si)


0119905 lowast 119868(119905)119889119905][int

infin

0119868(119905)]


2 A




2-Eu(TTA)




4 Conclusion


3(Phen-Si) complex


References






























2spherical parti-




















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




550 600 650 700

S1c

R1(C

PS120583

A)

Wavelength (nm)



(a)

250 300 350 400 450 500Wavelength (nm)


S1R

1c (

CPS

120583A

)


(b)


3-Phen Eu-BHHCT



5001000150020002500300035004000


mSiO2

T(

)



3(Phen-Si) and mSiO

2-

Eu(TTA)3(Phen-Si)


3(Phen-Si)) one










(a) (b)

(c) (d)















2 and


2-




2are





2-Eu(TTA)



3(Phen-Si)









500 550 600 650 700 750120582 (nm)

mSiO2


5D0rarr7F0

5D0rarr7F1

5D0rarr7F2

5D0rarr7F3

5D0rarr7F4

I(a

u)

(a)

mSiO2


250 300 350 400 450120582 (nm)

I(a

u)

(b)

0 05 1 15 2 25 3 35 40

1 times 107

2 times 107

3 times 107

4 times 107

5 times 107

6 times 107

Time (ms)


I(a

u)

(c)



2-Eu(TTA)

3(Phen-Si)

0

005

01

015

02

0 01 05 1 2

DO



3(Phen-Si) The


5D0rarr


0rarr

7F45D0rarr





2







(a) (b)




3(Phen-Si)


0119905 lowast 119868(119905)119889119905][int

infin

0119868(119905)]


2 A




2-Eu(TTA)




4 Conclusion


3(Phen-Si) complex


References






























2spherical parti-




















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




(a) (b)

(c) (d)















2 and


2-




2are





2-Eu(TTA)



3(Phen-Si)









500 550 600 650 700 750120582 (nm)

mSiO2


5D0rarr7F0

5D0rarr7F1

5D0rarr7F2

5D0rarr7F3

5D0rarr7F4

I(a

u)

(a)

mSiO2


250 300 350 400 450120582 (nm)

I(a

u)

(b)

0 05 1 15 2 25 3 35 40

1 times 107

2 times 107

3 times 107

4 times 107

5 times 107

6 times 107

Time (ms)


I(a

u)

(c)



2-Eu(TTA)

3(Phen-Si)

0

005

01

015

02

0 01 05 1 2

DO



3(Phen-Si) The


5D0rarr


0rarr

7F45D0rarr





2







(a) (b)




3(Phen-Si)


0119905 lowast 119868(119905)119889119905][int

infin

0119868(119905)]


2 A




2-Eu(TTA)




4 Conclusion


3(Phen-Si) complex


References






























2spherical parti-




















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




500 550 600 650 700 750120582 (nm)

mSiO2


5D0rarr7F0

5D0rarr7F1

5D0rarr7F2

5D0rarr7F3

5D0rarr7F4

I(a

u)

(a)

mSiO2


250 300 350 400 450120582 (nm)

I(a

u)

(b)

0 05 1 15 2 25 3 35 40

1 times 107

2 times 107

3 times 107

4 times 107

5 times 107

6 times 107

Time (ms)


I(a

u)

(c)



2-Eu(TTA)

3(Phen-Si)

0

005

01

015

02

0 01 05 1 2

DO



3(Phen-Si) The


5D0rarr


0rarr

7F45D0rarr





2







(a) (b)




3(Phen-Si)


0119905 lowast 119868(119905)119889119905][int

infin

0119868(119905)]


2 A




2-Eu(TTA)




4 Conclusion


3(Phen-Si) complex


References






























2spherical parti-




















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




(a) (b)




3(Phen-Si)


0119905 lowast 119868(119905)119889119905][int

infin

0119868(119905)]


2 A




2-Eu(TTA)




4 Conclusion


3(Phen-Si) complex


References






























2spherical parti-




















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls






























2spherical parti-




















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls













ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls



Luminescence Properties of Mesoporous Silica

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